<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
	#hd{
		width: 500px;
		height: 500px;
		margin: 0 auto;
		background: purple;/*所有浏览器*/
		background: blue\9;/*所有ie*/
		background: green\0;/*ie8 ie9*/
		+background: orange;/*ie6 ie7*/
		_background: yellow;/*ie6*/

		+margin-top: 100px;
		_margin-top: 0px;
	}
	:root #hd{
		background: pink\9;
	}
</style>
</head>

<body>

<div id="hd"></div>

</body>
</html>
